Cross-flow plate heat and/or moisture exchanger

ABSTRACT

The invention relates to a cross-flow plate heat and/or moisture exchanger having plates which are arranged above, below or next to one another, and form alternating flow passages for a first and a second fluid. According to the invention, for a cross-flow plate heat and/or moisture exchanger of this type, in order to achieve an improved transfer performance and an increased pressure stability in relation to differential pressures between the two fluids, each plate (2) has a first cross-flow region (4), a following counter flow region (6) in the flow direction of the first cross-flow region (4), and a following second cross-flow region (10) in the flow direction of the counter flow region (6). The cross-flow regions (4, 10) of neighbouring plates are to form flow channels (5, 11) running approximately perpendicular to one another, wherein the counter flow regions (6) of neighbouring plates form counter flow channels (7) running approximately parallel to one another and the first or second cross-flow region (4, 10) of each plate (2) corresponds to the second or first cross-flow region of each neighbouring plate in terms of the dimensions thereof, and is arranged above, below or next to same, and wherein the counter flow region (6) of each plate (2) corresponds to the counter flow region of each neighbouring plate (3) in terms of the dimensions thereof, and is arranged above, below or next to same.

The invention relates to a cross-flow plate heat and/or moisture exchanger having plates that are above, below or next to one another and form alternating flow passages for a first and a second fluid.

Based on the above-mentioned state of the art the invention is based on the requirement to provide an improved cross-flow plate heat and/or moisture exchanger that on the one hand exhibits better transfer performance during the transfer of heat and/or moisture between the two fluids and that moreover has increased pressure stability in relation to differential pressures between the two fluid flows.

According to the invention this requirement is met in that each plate of the cross-flow plate heat and/or moisture exchanger has a first cross-flow region, a counter-flow region downstream of the first cross-flow region in flow direction and a second cross-flow region downstream of the counter-flow region in flow direction, in that the cross-flow regions of adjacent plates form flow passages running approximately perpendicular to each other, in that the counter-flow regions of adjacent plates form flow passages running approximately parallel to one another, in that the first or the second cross-flow region of each plate in terms of its dimensions corresponds to the second or first cross-flow region of each adjacent plate and is above, below or next to same, and in that the counter-flow region of each plate in terms of its dimensions corresponds to the counter-flow region of each adjacent plate and is above, below or next to same.

Due to this design of the two differently constructed plates that are combined to form the cross-flow plate heat and/or moisture exchanger, it is achieved that the two fluids flowing through the cross-flow plate heat and/or moisture exchanger flow essentially anti-parallel to one another, as a result of which the efficiency of the cross-flow plate heat and/or moisture exchanger is considerably improved in comparison to corresponding aggregates known from the state of the art. Due to the flow passages running perpendicular to one another a mechanically stable design of the cross-flow plate heat and/or moisture exchanger is obtained. Since a counter-flow region is provided in each flow passage of the cross-flow plate heat and/or moisture exchanger according to the invention, it is ensured that the two fluids in this counter-flow region are guided past each other in an approximately anti-parallel manner. According to the invention it has become possible to steer the flow direction of the first fluid in direction of the entry of the second fluid so that the temperature or the moisture of the first fluid can move closer to the entry temperature or moisture of the second fluid. Similarly the temperature and/or the moisture of the second fluid can move closer to the entry temperature or moisture of the first fluid. By proceeding in this way high degrees of transfer are achievable that lie in the range of up to 90%.

The first cross-flow region of each plate causes the respective fluid flow to be evenly distributed across the counter-flow region of each plate. Due to the difference in design of the adjacent plates, these can mutually support each other very well, wherein nevertheless, in the area of the respective counter-flow regions, an approximately parallel progression of the respective flow passages is made possible.

In order to ensure that the stability of the plate packet of the cross-flow plate heat and/or moisture exchanger according to the invention also in the area of the counter-flow regions of the plates is of high quality even for the most varied pressures in the different fluids, it is advantageous if the counter-flow passages of the cross-flow region of each adjacent plate extend at a small acute angle of preferably 5 to 25°. This ensures an approximately parallel progression of the counter-flow passages formed by the adjacent plates in the adjacent flow passages, wherein moreover it is ensured that the adjacent plates are mechanically firmly supported against each other.

When the direction of counter-flow passages of the counter-flow regions of the plates changes, turbulences can be initiated in the flows of the two fluids that can contribute to an improvement of the transfer conditions of heat and/or moisture right through the plates between the two fluids.

In order to keep the installation cost for the cross-flow plate heat and/or moisture exchanger according to the invention to a minimum and in order to be able to ensure reliable sealing on the plate edges at a minimum of engineering effort, it is advantageous if the plates are shaped in the form of a rectangle or a square.

According to an advantageous embodiment of the cross-flow plate heat and/or moisture exchanger according to the invention the counter-flow regions of each plate are shaped as an approximate oval or ellipse extending between two opposing corners of the plate.

According to a further advantageous embodiment of the cross-flow plate heat and/or moisture exchanger according to the invention the general flow direction A, B through the cross-flow plate heat and/or moisture exchanger, of the two fluids separated from each other by the plates, is chosen such that the two fluids flow through the counter-flow regions of the cross-flow plate heat and/or moisture exchanger in counter direction, i.e. approximately anti-parallel.

If walls of the flow passages of the cross-flow regions that are between the plates, are formed in a uniform or uninterrupted manner, the flow conditions in the cross-flow regions of the cross-flow plate heat and/or moisture exchanger according to the invention are comparatively regular and orderly, which for certain requirement profiles on the cross-flow plate heat and/or moisture exchanger is convenient and advantageous.

If the requirement profiles for the cross-flow plate heat and/or moisture exchanger according to the invention are of a different kind, i.e. if more turbulent flow conditions are desired in the cross-flow regions thereof, it is convenient if walls of the flow passages of the cross-flow regions between the plates comprise interruptions.

Particularly advantageous materials for the plates of the cross-flow plate heat and/or moisture exchanger according to the invention have proved to be aluminum and plastic, preferably PET plastic, in particular then, when the cross-flow plate heat and/or moisture exchanger according to the invention is to be used merely for temperature transfer between the two fluids.

If the cross-flow plate heat and/or moisture exchanger according to the invention is to be used also or predominantly for moisture or enthalpy exchange between the two fluids, it is advantageous if the plates are configured as membrane plates. In this case each membrane plate comprises a membrane layer and a support layer. By means of the membrane layer enthalpy can be transferred between the two fluids. The at least one support layer is configured perforated. By means of the perforated support layer the membrane plate can be given a specifiable mechanical strength and a spatial structure, wherein both the mechanical strength and the spatial structure can be permanently maintained.

The membrane layer of the plates is conveniently formed of a suitable plastic material, preferably a polyurethane or a polymer material.

The support layer of the plates is conveniently formed of a suitable fleece material, preferably a polyester material.

The invention will now be described in detail by way of an embodiment with reference to the drawing, in which

FIG. 1 shows an embodiment of a plate of the first design for a cross-flow plate heat and/or moisture exchanger according to the invention comprising two differently constructed plates;

FIG. 2 shows an embodiment of a plate of the second design for a cross-flow plate heat and/or moisture exchanger according to the invention comprising two differently constructed plates; and

FIG. 3 shows a schematic diagram of a cross-flow plate heat and/or moisture exchanger according to the invention comprising embodiments of plates depicted in FIGS. 1 and 2.

A cross-flow plate heat and/or moisture exchanger 1 according to the invention shown in a schematic diagram in FIG. 3 consists of a plate packet composed of plates 2, 3 of different design or construction. Within the plate packet the plates 2 and the plates 3 are in an alternating manner, i.e. a plate 2 of the first construction type is followed respectively by a plate 3 of the second construction type. Accordingly each plate 2 of the first construction type has two adjacent plates 3 of the second construction type and vice-versa. In the case of the embodiment shown in FIG. 3, the plates 2, 3 are on top of each other. It is, of course, possible to arrange the plates 2, 3 adjacently to each other.

The two sides of the plates 2, 3 facing each other limit flow passages for a first fluid that flows through the cross-flow plate heat and/or moisture exchanger 1 of FIG. 1 in a general direction indicated by arrows A, and for a second fluid that flows through the cross-flow plate heat and/or moisture exchanger 1 of FIG. 2 in a general direction indicated by arrows B. The general direction A of the first fluid is approximately perpendicular to the general direction B of the second fluid.

The flow passages for the first fluid and for the second fluid are in an alternating manner in the plate packet shown in FIG. 3 made up of plates 2, 3.

The flow passages for the first fluid are determined by the design shown in FIG. 1 of the plate 2 of the first construction type. The flow passages for the second fluid are determined by the design shown in FIG. 2 for the plate 3 of the second construction type.

The plates 2, 3 of the cross-flow plate heat and/or moisture exchanger 1 may be made of any suitable material, for example aluminum or a PET material.

If the cross-flow plate heat and/or moisture exchanger 1 is also to be used essentially for moisture or enthalpy exchange between the two fluids that flow through same, the plates 2, 3 of the cross-flow plate heat and/or moisture exchanger 1 are configured as membrane plates. The respective membrane plates consist of a membrane layer by means of which enthalpy can be transferred between the two fluids, and at least one perforated support layer by means of which a specifiable mechanical strength and a spatial structure can be imparted to the membrane plate and be maintained therein.

The membrane layer of plates 2, 3 is then formed from a suitable plastic material, in particular a polyurethane or a polymer material.

The support layer of the plates 2, 3 is then formed from a suitable fleece material, preferably from a polyester fleece or similar.

The flow passages that are provided in the cross-flow plate heat and/or moisture exchanger 1 for the first fluid, are designed according to the structure of plate 2 of the first construction type as depicted in the following in FIG. 1. In case of the embodiment shown in FIG. 1 the plate 2 has a first cross-flow region 4, into which the first fluid enters. The first cross-flow region 4 comprises flow passages 5 extending in parallel, through which the first fluid is guided to a counter-flow region 6 downstream of the first cross-flow region 4. In the embodiment shown the counter-flow region 6 comprises a larger number of counter flow passages 7 in comparison to the number of flow passages 5 of the first cross-flow region 4. The counter-flow passages 7 are at an incline to the flow passages 5. Moreover the counter-flow passages 7, as from a certain length, comprise length portions of varying direction. The varying length of the counter-flow passages 7 stems from the fact that the counter-flow region 6 of the first plate 2 extends from the right upper corner 8 thereof in FIG. 1 to the left lower corner 9 thereof in FIG. 1 and comprises an elliptical or oval shape tapering in direction of the corners 8, 9.

The first fluid is guided through the multiplicity of counter-flow passages 7 to a second cross-flow region 10 of the plate 2. The second cross-flow region 10 comprises flow passages 11 that extend in parallel to the flow passages 5 of the first cross-flow region 4 and that respectively extend in the general direction A, in which the first fluid flows through the cross-flow plate heat and/or moisture exchanger 1.

The flow passages that are provided in the cross-flow plate heat and/or moisture exchanger 1 for the second fluid, are designed according to the structure of plate 3 of the second construction type as depicted in the following in FIG. 2. In case of the embodiment shown in FIG. 2 the plate 3 has a first cross-flow region 12, into which the second fluid enters. The first cross-flow region 12 comprises flow passages 13 extending in parallel, through which the second fluid is guided to a counter-flow region 14 downstream of the first cross-flow region 12. In the embodiment shown the counter-flow region 14 comprises a larger number of counter flow passages 15 in comparison to the number of flow passages 13 of the first cross-flow region 12. The counter-flow passages 15 are at an incline to the flow passages 13. Moreover the counter-flow passages 15, as from a certain length, comprise length portions of varying direction. The varying length of the counter-flow passages 15 stems from the fact that the counter-flow region 14 of the second plate 3 extends from the right upper corner 16 thereof in FIG. 2 to the left lower corner 17 thereof in FIG. 2 and comprises an elliptical or oval shape tapering in direction of the corners 16, 17.

The second fluid is guided through the multiplicity of counter-flow passages 15 to a second cross-flow region 18 of the plate 3. The second cross-flow region 18 comprises flow passages 19 that extend in parallel to the flow passages 13 of the first cross-flow region 12 and that respectively extend in the general direction B, in which the second fluid flows through the cross-flow plate heat and/or moisture exchanger 1.

As already explained, the plate packet of the cross-flow plate heat and/or moisture exchanger 1 is constructed by arranging the differently constructed plates 2, 3 depicted in FIG. 1 and FIG. 2 in an alternating manner on top of each other. As can be seen in FIG. 1 and FIG. 2, the first cross-flow region 4 of plate 2, in terms of its layout and its dimensions, corresponds to plate 3 depicted in FIG. 2. Analogously the second cross-flow region 10 of plate 2 depicted in FIG. 1, in terms of its shape and its dimensions, corresponds to the first cross-flow region 12 of plate 3 depicted in FIG. 2. The first fluid and the second fluid, in the cross-flow regions 4, 10, 12, 18 of the two plates 2, 3, flow in their general directions A or B and thus approximately perpendicular to each other.

The plates 2, 3 in the embodiments shown in FIGS. 1 and 2 are shaped approximately as a square. Since the contours and the layout of the cross-flow regions 4 and 18/10 and 12 of plates 2, 3 correspond to each other, this also applies to the contours and the layout of the counter-flow regions 6, 14 of the two plates 2,3.

In the counter-flow regions 6 and 14 the first fluid and the second fluid flow in an opposite or anti-parallel flow direction. The directional changes of the counter-flow passages 7 and 15 provided in the counter-flow regions 6, 14 cause irregularities or turbulences of the flows of the first fluid and of the second fluid that contributes to an improvement in the heat and/or moisture transfer between the fluids 1, 2.

The general flow direction of fluid 1 in the counter-flow region 6 as well as of fluid 2 in the counter-flow region 14, with the plates 2, 3 shown in FIGS. 1 and 2, occurs at an angle of approximately 45° to the general directions A and B of fluid 1 and fluid 2, respectively. The counter-flow passages 7 of the counter-flow region 6 of plate 2 are, in the case of plates 2, 3 depicted in FIGS. 1 and 2, inclined by a comparatively small angle that may be between 5° and 25°, in relation to the counter-flow passages 15 of the counter-flow region 14 of plate 2. This ensures that the mechanical structure of the plate packet forming the cross-flow plate heat and/or moisture exchanger 1 is stable with the distances between plates 2, 3 remaining unchanged even in the area of their counter-flow regions 6, 14. When assembling the plate packet of the above-described cross-flow plate heat and/or moisture exchanger 1 it must be ensured that the entry section associated with the first fluid and the entry section associated with the second fluid are in relation to one another in such a way that the first and the second fluid flow in opposite directions in the counter-flow regions 6, 14.

In the exemplary embodiment shown walls 20 of the flow passages 5 of the first cross-flow region 4 of plate 2, walls 21 of the flow passages 11 of the second cross-flow region 10 of plate 2, walls 21 of the flow passages 13 of the first cross-flow region 12 of plate 3 and walls 23 of flow passages 19 of the second cross-flow region 18 of plate 3 are constructed without interruptions, i.e. in a uniform and continuous manner. Interruptions between the said walls, in the case of plates 2, 3 depicted in FIGS. 1 and 2, exist in particular at the transitions between the cross-flow regions 4, 10, 12, 18 and the counter-flow regions 6, 14.

Where more turbulent flow conditions are desired or necessary in the cross-flow regions 4, 10, 12, 18, the walls of flow passages 5, 11, 13, 19 may, of course, also have interruptions. 

1. A cross-flow plate heat and/or moisture exchanger comprising: plates that are above, below or next to one another and form alternating flow passages for a first and a second fluid, each plate having a first cross-flow region a counter-flow region downstream of the first cross-flow region in flow direction and a second cross-flow region downstream of the counter-flow region in flow direction, the cross-flow regions of adjacent plates forming flow passages running approximately perpendicular to one another, the counter-flow regions of adjacent plates forming counter-flow passages running approximately parallel to one another, the first or second cross-flow region of each plate in terms of its dimensions corresponding to the second or first cross-flow region of each adjacent plate and being above, below or next to same, and the counter-flow region of each plate in terms of dimensions corresponding to the counter-flow region of each adjacent plate and being above, below or next to same.
 2. The cross-flow plate heat and/or moisture exchanger according to claim 1, wherein the counter-flow passages of the counter-flow region of each plate extend at a small acute angle of 5° to 25° to the counter-flow passages of the counter flow region of each adjacent plate.
 3. The cross-flow plate heat and/or moisture exchanger according to claim 1, wherein the direction of counter-flow passages of the counter-flow regions of the plates changes.
 4. The cross-flow plate heat and/or moisture exchanger according to claim 1, wherein the plates are of square or rectangular shape.
 5. The cross-flow plate heat and/or moisture exchanger according to claim 1, wherein the counter-flow regions of each plate are of approximately oval or elliptical shape and extend between two opposite corners of the plate.
 6. The cross-flow plate heat and/or moisture exchanger according to claim 1, wherein the general flow direction of the two fluids separated from each other by the plates through the cross-flow plate heat and/or moisture exchanger is chosen such that the two fluids flow through the counter-flow regions of the cross-flow plate heat and/or moisture exchanger in counter direction.
 7. The cross-flow plate heat and/or moisture exchanger according to claim 1, wherein walls of the flow passages of the cross-flow regions that are between the plates, are formed in a uniform or interruption-free manner.
 8. The cross-flow plate heat and/or moisture exchanger according to claim 1, wherein walls between the plates, of the flow passages of the cross-flow regions comprise interruptions.
 9. The cross-flow plate heat and/or moisture exchanger according to claim 1, wherein the plates are formed of aluminum.
 10. The cross-flow plate heat and/or moisture exchanger according to claim 1, wherein the plates formed of plastic.
 11. The cross-flow plate heat and/or moisture exchanger according to claim 1, wherein the plates are formed of membrane plates, with a membrane layer for transfer of enthalpy between the two fluids, and at least one perforated support layer that can impart a specifiable mechanical strength and a spatial structure to the membrane plate and be maintained therein.
 12. The cross-flow plate heat and/or moisture exchanger according to claim 11, wherein the membrane layer of the plates is formed of a suitable plastic material, preferably a polyurethane or a polymer material.
 13. The cross-flow plate heat and/or moisture exchanger according to claim 11, wherein the support layer of the plates is formed of a suitable fleece material. 